Comminuting device

ABSTRACT

A comminuting device includes a comminuting chamber which has a bottom wall and a circumferential wall which extends upwards from the bottom wall. The device also includes a rotatably driven drive shaft which extends essentially orthogonal to the bottom wall, and at least one comminuting element which is disposed next to the bottom wall. This at least one comminuting element can be made to perform a rotary movement about the drive shaft by the drive shaft. A plurality of additional comminuting elements which can be made to perform a rotary or revolving movement about the drive shaft ( 22 ) by means of the drive shaft are arranged above the at least one comminuting element comminuting element disposed next to the bottom wall.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of International Patent ApplicationNo. PCT/DE2003/009484 filed Aug. 27, 2003, which claims priority toGerman Patent Application No. 102 39 820.8 filed Aug. 29, 2002, both ofwhich applications are hereby incorporated by reference in theirentireties herein.

FIELD OF THE INVENTION

The invention relates to devices for comminuting. In particular theinvention relates to a device, which includes a comminution chamberhaving a bottom wall and a circumferential wall projecting upward fromthe bottom wall, and which is additionally provided with a rotationaldrive shaft extending essentially orthogonal to the bottom wall and withat least one comminution element arranged neighboring to the bottom walland capable of being set in revolving motion about the drive shaft bythe drive shaft

BACKGROUND OF THE INVENTION

Such comminuting devices are increasingly being employed in the recoveryof raw materials. In particular, this may involve composite materialssuch as occur for example in the preparation for recycling of electricand electronic appliances or components, recycling monomaterials offerrous metals, non-ferrous metals, synthetics or wood, fractions fromother preceding coarse comminution processes in the recycling industry,or slags from processes of combustion.

A generic comminuting device is disclosed for example in EP 0,606,891B1. This comminuting device includes a comminution chamber in which arotor with vertical shaft is arranged. To this vertical shaft,immediately neighboring upon the bottom wall of the comminution chamber,two chains are attached as comminution elements. The comminution chamberis charged with material to be comminuted through an opening provided inthe vicinity of its ceiling. When the material has been comminuted tothe desired extent, a trap arranged in the circumferential wall of thecomminution chamber near the bottom wall is opened to discharge thecomminuted material. A disadvantage of this known comminuting device isthat the material to be comminuted can only be comminuted batchwise,i.e. that the process of comminution is discontinuous.

Consideration is now being given to ways of improving comminutingdevices and process. In particular, attention is directed to comminutingdevices and processes that can be operated continuously.

SUMMARY OF THE INVENTION

A comminuting device which can be operated continuously is provided. Thedevice includes a comminution element neighboring upon the bottom wall,and a plurality of additional comminution elements that are capable ofbeing set in revolving motion about the drive shaft by said shaft. Thisconfiguration ensures that the material to be comminuted that is chargedin the comminution chamber is multiply exposed to the impact of theblows of the comminution elements before it arrives at the bottom of thecomminution chamber. Thus, the material to be comminuted cannot simplyfall to the bottom and leave the comminution chamber again through thedischarge opening under the very first blow of a comminution element, asis possible in the case of the comminuting device disclosed in EP0,606,891 B1. Instead, a plurality of blows ensures an adequatecomminution of the material to be comminuted before it arrives in thedischarge area. Therefore, the material to be comminuted can be chargedinto the comminution chamber continuously.

Since the comminuting device according to the invention is preferablyalso employed for pre-comminution of the material to be comminuted, andthe principal or final comminution of the material comminuted by ittakes place in a comminuting device distributed by Applicant under thedesignation “Rotorprallmühle RPMV” [rotor impact mill RPMV]. it istolerable if occasionally some not adequately comminuted object isdischarged from the comminuting device according to the invention. Suchan object, because of its size, can be separated in simple manner fromthe material discharged and returned to the comminuting device forrenewed pre-comminution.

In order in simple manner to prevent the discharge of large objects,however, it is preferred that at least a portion of the circumferentialwall be configured as a grating. This grating, which may be made up of aplurality of members preferably extending vertically, and arranged at apredetermined distance from each other, serves as a sieve, determiningthe size of material discharged from the comminuting device according tothe invention. The material discharged from the comminuting deviceaccording to the invention is especially suitable as charging materialfor the “Rotorprallmühle RPMV” if the value of the predetermineddistance is about 38 mm. In order to withstand the ‘bombardment’ withmaterial to be comminuted, i.e. in order to diminish wear on the membersof the grating, the members may be made of wear-resistant steel or ofcast material.

So that a controlled discharge of the material that has passed throughthe grating may be assured, the grating may be surrounded by an outerjacket. To prevent wires or similar fine objects from getting stuck inthe space between the grating and the outer jacket, it is proposed thatthe outer jacket have a predetermined minimum distance from the grating,amounting for example to about 200 mm. In the space between the gratingand the outer jacket, the comminuted material may drop onto a catchmeans preferably of funnel-shaped configuration, for comminutedmaterial, which is disposed at the bottom end of the outer jacket. Fromthis catch means (e.g., a funnel-shaped hopper), the comminuted materialmay then be discharged downward, for example.

In addition to the circumferential wall, the bottom wall may also beconfigured as a grating, at least in part. The comminuted materialpassing through the bottom grating may also be discharged from thecomminuting device by way of the funnel-shaped catch means.

In addition to the discharge by way of the funnel-shaped catch means, anopening openable and closable at will may be provided in thecircumferential wall near the bottom wall, i.e. a discharge openingcorresponding to the opening in EP 0,606,891 B1. As has already beenexplained above, this opening, if the comminuting device according tothe invention includes neither a grating nor a catch hopper, may be thesole discharge opening of the comminuting device. Alternatively,however, it is possible also to use this opening as additional dischargeopening. But in any case, this discharge opening may be used to emptythe comminution chamber in event of overloading of the drive or blockingof the drive shaft. For opening and/or closing of the opening at will, aslide valve may be provided, dynamically actuable by means of ahydraulic cylinder. The size of the gap cleared by the slide valve maybe used to influence the size of the material discharged or to influencethe residence time in the comminution chamber of the material to becomminuted. Control of the size of this gap may be integrated into theover-all process of controlling the comminuting device.

To facilitate installation and maintenance work on the grating or/andthe comminution elements, provision may be made for at least acircumferential segment of the outer jacket to be swingably arranged,preferably about an axis extending essentially vertical, or/and for atleast a circumferential segment of the grating to be swingably arranged,preferably about an axis extending essentially vertical, or/and for aswingable circumferential segment of the grating and a swingablecircumferential segment of the outer jacket to form a jointly manageableunit. This swingability may be provided by simple design and productiontechniques if the outer jacket has a polygonal, preferably an octagonal,contour. In the case of an octagonal contour, the comminuting device mayfor example be provided with a grating in the region of six of the eightsides of the comminuting device, whereas on the other two sides,preferably diametrically opposed to each other, functional parts may beprovided, for example the charge opening for charging material to becomminuted and the discharge opening, making possible the completeemptying of the comminution chamber.

As is known per se from EP 0,606,891 B1, at least one comminutionelement, preferably the element neighboring to the bottom wall, may bemade up of a chain. A comminution chain has the advantage that, whennecessary, it can escape upward, diminishing wear on the bottom wall.

Moreover, however, it is also possible that at least one comminutionelement may be made up of an impact member. Impact members, compared toimpact chains, have the advantage that they strike the material to becomminuted with greater momentum, and therefore comminute it moreeffectively. In order to make possible an escape of the impact memberswhen necessary and thus keep them from breaking off, provision may alsobe made for the impact member to be articulately attached to the driveshaft, preferably swingably about an axis extending preferably parallelto the drive shaft.

If the comminution elements are helically arranged on the drive shaft,and this preferably in such manner that a comminution element closer tothe bottom wall is arranged to run ahead of a comminution element moredistant from the bottom wall in the direction of revolution about thedrive shaft, then the comminution elements working together on thematerial to be comminuted can exert a force opposed to gravity. Thisleads to a prolonged residence of the material to be comminuted in thecomminution chamber, and therefore to its better comminution. For thispurpose, the drive shaft may, for example, be configured as a hexagonalshaft.

In development of the invention, it is proposed that the comminutionelements be arranged on the drive shaft in planes of comminutionelements, having a predetermined minimum distance between them, whichmay, for example, be about 120 mm. Here, the predetermined minimumdistance ensures, firstly, that the suspension of the comminutionelements on the drive shaft is of sufficiently stable construction, andsecondly that even fairly large fragments of the material to becomminuted can move gradually between the comminution elements towardsthe bottom wall. In this way, it is ensured that all comminutionelements can contribute to the comminution and therefore will wear downuniformly.

If between the free end of at least one of the comminution elements andthe circumferential wall a predetermined distance is provided, then thiscan reduce the risk of a jamming or wedging of the material to becomminuted between the comminution elements and the circumferentialwall, with favorable effects on wear of the circumferential wall,especially when this is configured as a grating.

If at least one annular attachment is provided, projecting inward fromthe circumferential wall and preferably of funnel-shaped configuration,then the material that falls downward in the existing gap between thefree end of the comminution elements and the circumferential wall can bereturned to within reach of the comminution elements. Besides, theannular attachment may be employed as protection for the fasteningelements, preferably threaded bolts, with which the elements of thegrating are fastened to a bent flattened steel member serving assuspension means.

In manner known per se, a charge opening may be provided in the regionof the upper edge of the circumferential wall, for charging material tobe comminuted. Such a charge opening may extend from the upper edge ofthe circumferential wall over a predetermined distance towards thebottom wall.

In this way, the material to be comminuted may be introduced at least inpart laterally into the comminution chamber, reducing the free height tobe provided in the region of the comminuting device according to theinvention in view of the structural height of the comminuting deviceitself and the size of the material to be comminuted. As alreadysuggested above, the charge opening is preferably provided in acircumferential region of the comminuting device not configured with agrating.

In order to be able to prevent the material to be comminuted from beingknocked out of the comminution chamber through the charge opening againupon first contact with a comminution element, only one comminutionelement may be provided in the uppermost plane of comminution elements,and also if desired in at least one additional comminution element planearranged below. In addition or alternatively, at least the at least oneuppermost comminution element may be of shorter configuration than theremaining comminution elements. Finally, a recoil of charged materialmay also be prevented in that a supply passage preceding the chargeopening is of angled configuration.

In order to be able to secure a stable rotation of the drive shaftdespite the plurality of comminution elements, it is proposed that thedrive shaft be rotatably mounted both on the bottom wall and on aceiling wall of the comminution chamber.

In manner known per se, the drive motor may be connected to the driveshaft by a belt drive. Here, this belt drive may equalize speedfluctuation of the drive shaft due to the impact loading in simplemanner, so that these speed fluctuations will not load the drive motor.The speed of the drive shaft may be between about 200 rpm and about2,000 rpm, preferably between about 500 rpm and about 1,000 rpm.

Finally, a connection opening may be provided for connection of anexhaust device, preferably in a circumferential region without grating.This connection opening may also be arranged behind an impact wall, sothat wires and the like particles whose mass exceeds a predeterminedvalue will not be aspirated, owing to their inertia.

BRIEF DESCRIPTION OF THE DRAWING

Further features of the invention, its nature, and various advantageswill be more apparent from the following detailed description and theaccompanying drawings, wherein like reference characters represent likeelements throughout, and in which:

FIG. 1 represents a sectional view of a comminuting device according tothe invention, at the line I-I in FIG. 3;

FIG. 2 represents a sectional view of a comminuting device according tothe invention, at the line II-II in FIG. 3;

FIG. 3 represents a top view of a comminuting device according to theinvention; and,

FIG. 4 shows a graph to illustrate the service possibilities of thecomminuting device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides comminuting devices and comminutingprocesses. Features of an exemplary device and process are describedherein with reference to FIGS. 1-4.

FIG. 1 shows a comminuting device according to the invention, which isquite generally designated device 10. It includes a comminution chamber12 bounded by a circumferential wall 14, a bottom wall 16 and a ceilingwall 18. In the neighborhood of the bottom wall 16 and the ceiling wall18, bearing locations 20 are provided for a drive shaft 22, driven by adrive motor 24 by way of a belt drive 26 in the direction of the arrow P(see FIG. 3).

On the therefore essentially vertical drive shaft 22, a plurality ofcomminution elements 28 are arranged in pairs in comminution elementplanes one above another. Only the two uppermost planes, i.e.comminution element planes next to the ceiling wall 18, comprise only asingle comminution element 28. The comminution elements of the planenext to the bottom wall 18 are configured as impact chains 28 a, whilethe remaining comminution elements are configured as impact members 28b. The impact members 28 b are suspended in flying/cantileverarrangement on the drive shaft 22, i.e. swingable about an axisextending essentially parallel to the drive shaft 22. For the sake ofclarity of the representation in FIG. 1, this is shown only for theimpact member 28 b′ of the uppermost plane of comminution elements. Thecomminution element planes have a distance d₁ from each other (see FIG.2).

In the representation according to FIG. 1 at the upper left, thecomminution chamber 12 has an entrance 30 for the material to becomminuted. So that this material will not recoil into the entrance 30immediately upon first contact with the impact members 28 b, each of theuppermost two planes of comminution elements is provided with only oneimpact member 28 b. In how many planes of comminution elements only oneimpact member 28 b is provided depends on how far the entrance 30extends downward along the height of the circumferential wall 14.Besides, the impact members 28 b of the uppermost planes of comminutionelements are configured shorter than the remaining impact members. Thisis indicated in FIG. 1 only for the uppermost impact member 28 b′. Inprinciple, however, the impact members 28 b of several planes ofcomminution elements may be curtailed, and this preferably with a‘pine-tree-like’ lengthwise staggering. How many comminution elementplanes are involved in the curtailment of the impact members dependsamong other things on how far the entrance 30 extends along the radiusof the comminution chamber 12 towards the drive shaft 22.

By contact with the rotating impact members 28 b, the material chargedthrough the entrance opening 30 into the comminution chamber 12 iscomminuted. Larger pieces here reside in the neighborhood of theentrance 30 until they are broken by the uppermost impact members 28 binto fragments whose size depends among other things on the distance d,between the comminution element planes, the circumferential offset ofthe impact members of neighboring comminution element planes and thespeed of the drive shaft 22. Then these fragments move downward bygravity through the various comminution element planes, being furthercomminuted through the impact effect of the impact members 28 b and/orthe impact chains 28 e.

Especially small fragments are flung radially outward against thecircumferential wall 14 by the impact of the members 28 b. Thiscircumferential wall 14, as shown in FIG. 3, consists of a grating 32composed of a plurality of grating members 32 a arranged vertically. Thegrating members 32 a have a mutual distance d₂ so that fragments whosedimensions are smaller than the quantity d₂ pass through the gratings 32and can leave the comminution chamber 12. In order to ensure an orderlydischarge of this comminuted material, the circumferential wall 14and/or the grating 32 are surrounded by an outer jacket 34 opening atits bottom end 34 a into a catch hopper 36. The lower opening 36 a ofthe hopper 36 guides the comminuted material out of the comminutingdevice 10.

To prevent excessive stress and hence excessive wear on the gratingmembers 32 a by the fragments of material to be comminuted, a distanced₃ is provided between the free ends of the impact members 28 b and thecircumferential wall 14 and/or the gratings 32. Owing to this distanced₃, which is greater than the distance d₂ of the members 32 a, however,there is the danger that material not yet sufficiently comminuted maybounce off the grating 32 and drop between the grating 32 and the freeends of the impact members 28 b onto the bottom plate 16. This wouldlead to an excessive stress on the impact chains 28 a and the lowermostimpact members 28 b. Therefore, in this intervening space 33, twofunnel-shaped annular attachments 38 are provided, which return materialfalling down into this space to the region of the impact members 28 b.In this way, a uniform wear of all comminution elements 28 can beensured.

If, owing to wrong choice of operating parameters, for example a toorapid supply of the material to be comminuted, too slow a speed of thedrive shaft 22, or the like, some excessive collection of not adequatelycomminuted material should nevertheless occur in the region of thebottom wall 16, then this undesired accumulation of material can bethrown out of the comminution chamber 12 through a lateral opening 40.This lateral opening 40 is closable by means of a trap 42, openable orclosable at will by means of a hydraulic cylinder 44. A protectivecasing 46 provides for an orderly ejection of material without risk ofdanger to operating personnel.

Finally, FIG. 1 also shows a connection 48 for an exhaust device 49,aspirating dust and the like from the comminution chamber 12 and fromthe annular space 33 between grating 32 and outer jacket 34.

As shown in FIG. 3, the comminuting device 10 according to theinvention, i.e. in particular its outer jacket 34, comprises anoctagonal cross-section. Here the three lower side surfaces of the outerjacket 34 in FIG. 3 and the circumferential segment of the grating 32associated with them are combined into a unit 50, which can be swungaway from the rest of the comminuting device 10 about a vertical axis Ato afford access to the comminution chamber 12 and in particular to thedrive shaft 20 and to the comminution members 28 for maintenance oroperating personnel. Furthermore, each of the three side surfaces of theouter jacket 34 comprises a maintenance flap 54, affording access to theoutside of the grating 32 after being swung away from the outer jacket34, for example, in order to replace individual grating members 32 a.Similarly, the three upper side surfaces of the outer jacket 34 arecombined into a corresponding unit 52 capable of being swung away fromthe remaining comminuting device 10 about the axis B.

In the circumferential segments corresponding to the remaining two sidesurfaces of the outer jacket 34, the drive motor 24 including the beltdrive 26, the ejection opening 40, the entrance 30 and the connectingnozzle 48 for the exhaust device 49 are arranged. In these twocircumferential segments, the circumferential wall 14 is configuredcontinuously, i.e. without grating.

In FIG. 4, the conception of a comminution plant 60 is represented inthe form of a process diagram, to be employed for recovery of rawmaterials including compound material, from equipment, such asrefrigerators, washing machines, television sets, computers, motorvehicle parts or the like.

In this plant 60, the comminuting device 10 according to the inventionserves for pre-comminution of the material to be comminuted. The finalcomminution takes place in another comminuting device 62, for examplethe comminuting device distributed by Applicant under the designation‘Rotorprallmühle RPMV.’ Depending on the material to be comminuted ineach instance, it may be necessary or advantageous to precede thecomminuting device 10 according to the invention with an additionalcomminuting device 64 for coarse comminution, for example thecomminuting device disclosed in EP 0,606,891 B1.

On Detailed Course of Process

The material to be comminuted is introduced at 66 into the comminutingdevice 64 for coarse comminution. The coarsely comminuted materialdischarged therefrom at 68 is supplied to a screener 70, which separateslight material and discharges it at 72. The remaining material issupplied to the entrance 30 of the comminuting device 10 according tothe invention for pre-comminution. The pre-comminuted materialdischarged by way of the catch hopper 36 is passed on to anotherscreener 74, which again separates out light material.

To prevent clogging and hence blocking of the comminuting device 10,material not adequately comminuted is ejected through the lateralopening 40 and returned to the entrance 30 by way of the conveyor 41. Ifnecessary, un-comminuted material may be separated out completely anddischarged at 76.

Before the material provided by the screener 74 for principalcomminution is supplied to the comminuting device 62 at 78 for finalcomminution, ferromagnetic parts are separated out in a magneticseparator 80 and discharged at 82.

The comminuting device 62 may also be operated in partial circulation,i.e. material not sufficiently comminuted may be returned by way of aconveyor 79 to the entrance 78 of the comminution device 62. Followingthe principal or final comminution, a further screening takes place in ascreener 84 and a further separation of ferromagnetic particles in amagnetic separator 86, before the remaining finally comminuted materialis supplied to a classifying device 88 and a sorting device 90. If,owing to inadequate physical separation various materials renderimpossible a classification of certain fractions of the comminutedmaterial, then this unclassifiable fraction may be returned by way of aconveyor 89 to the entrance 78 of the comminuting device 62

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention.

1. A comminuting device, comprising: a comminution chamber having abottom wall and a circumferential wall projecting upward from the bottomwall, a rotationally drivable drive shaft extending essentiallyorthogonal to the bottom wall and at least one comminution elementarranged adjacent to the bottom wall and capable of being set inrevolving motion about the drive shaft by said shaft, and a plurality ofadditional comminution elements capable of being set in revolving motionabout the drive shaft by said shaft, which are disposed above thecomminution element adjacent to the bottom wall, wherein at least aportion of the circumferential wall of the comminution chamber isconfigured as a grating and wherein the grating is surrounded by anouter jacket, at the lower end of which a catch device is provided forcomminuted material, and characterized in that, in the circumferentialwall of the comminution chamber an opening adjacent to the bottom walland openable and closable at will is provided, which can be used as anadditional discharge opening.
 2. The comminuting device of claim 1,characterized in that the grating is composed of a plurality of membersthat extend about vertically, and are arranged at about a predetermineddistance d₂ from each other.
 3. The comminuting device of claim 1,characterized in that the outer jacket has a predetermined minimumdistance from the grating.
 4. The comminuting device of claim 1,characterized in that at least one circumferential segment of the outerjacket is swingably configured about an axis that extends essentiallyvertically.
 5. The comminuting device of claim 1, characterized in thatat least one circumferential segment of the grating is swingablyconfigured about an axis that extends essentially vertically.
 6. Thecomminuting device of claim 1, characterized in that a swingablecircumferential segment of the grating and a swingable circumferentialsegment of the outer jacket form a jointly manageable unit.
 7. Thecomminuting device of claim 1, characterized in that the outer jacketcomprises a polygonal contour shape.
 8. The comminuting device of claim1, characterized in that at least a portion of the bottom wall isconfigured as a grating.
 9. The comminuting device of claim 1,characterized in that at least one comminution element, comprises achain.
 10. The comminuting device of claim 1, characterized in that atleast one comminution element comprises an impact member.
 11. Thecomminuting device of claim 10, characterized in that the impact memberis articulated to the drive shaft, and is swingable about an axis thatextends about parallel to the drive shaft.
 12. The comminuting device ofclaim 1, characterized in that the comminution elements are arrangedhelically on the drive shaft so that a comminution element nearer to thebottom wall is arranged to run ahead more than a comminution elementmore distant from the bottom wall in the direction of revolution aboutthe drive shaft.
 13. The comminuting device of claim 1, characterized inthat the drive shaft is a hexagonal shaft.
 14. The comminuting device ofclaim 1, characterized in that the comminution elements are arranged onthe drive shaft in planes of comminution elements, wherein the planeshave about a predetermined minimum distance d₁ from each other.
 15. Thecomminuting device of claim 1, characterized in that, between the freeend of at least one of the comminution elements and the circumferentialwall, a predetermined distance d₃ is provided.
 16. The comminutingdevice of claim 1, characterized in that at least one annular attachmentprojecting inward from the circumferential wall is provided, wherein theannular attachment has a funnel-shaped configuration.
 17. Thecomminuting device of claim 1, characterized in that in the neighborhoodof the upper edge of the circumferential wall, a charge opening isprovided for supply of material to be comminuted.
 18. The comminutingdevice of claim 17, characterized in that the charge opening extendsfrom the upper edge of the circumferential wall over a predetermineddistance towards the bottom wall.
 19. The comminuting device of claim 1,characterized in that, at least one plane of the uppermost plane ofcomminution elements and the planes of comminution elements arrangedthereunder, consists a single comminution element.
 20. The comminutingdevice of claim 1, characterized in that at least one uppermostcomminution element is configured to be shorter than the othercomminution elements.
 21. The comminuting device of claim 1,characterized in that a supply passage preceding the supply opening hasan angled configuration.
 22. The comminuting device of claim 1,characterized in that the drive shaft is rotatably mounted both at thebottom wall and also at a ceiling wall of the comminution chamber. 23.The comminuting device of claim 1, characterized in that a drive motoris connected to the drive shaft by way of a belt drive.
 24. Thecomminuting device of claim 1, characterized in that a speed of thedrive shaft is between about 200 rpm and about 2,000 rpm, and an optimalspeed of the drive shaft is about 500 rpm and about 1,000 rpm.
 25. Thecomminuting device of claim 1, further comprising a connection openingfor an exhaust device.
 26. The comminuting device of claim 1, whereinthe catch device is of funnel shaped configuration.